diff --git a/Compiler/BackEnd/BackendDAECreate.mo b/Compiler/BackEnd/BackendDAECreate.mo
index c7391050e74..c3e5eff65a7 100644
--- a/Compiler/BackEnd/BackendDAECreate.mo
+++ b/Compiler/BackEnd/BackendDAECreate.mo
@@ -1050,7 +1050,7 @@ protected function lowerIfEquation
   input list<BackendDAE.Equation> inEqns;
   output list<BackendDAE.Equation> outEqns;
 algorithm
-  outEqn := matchcontinue(conditions,theneqns,elseenqs,conditions1,theneqns1,source,functionTree,inEqns)
+  outEqns := matchcontinue(conditions,theneqns,elseenqs,conditions1,theneqns1,source,functionTree,inEqns)
     local
       DAE.Exp e;
       list<DAE.Exp> explst;
diff --git a/Compiler/BackEnd/BackendDAEOptimize.mo b/Compiler/BackEnd/BackendDAEOptimize.mo
index 796e70bd3fb..2445bdbd40f 100644
--- a/Compiler/BackEnd/BackendDAEOptimize.mo
+++ b/Compiler/BackEnd/BackendDAEOptimize.mo
@@ -3310,7 +3310,6 @@ algorithm
         remeqns = BackendDAEUtil.listEquation(eqnslst);
         // do replacements in systems        
         systs = List.map1(systs,removeProtectedParameterswork,repl);
-        BackendDump.dump(BackendDAE.DAE(systs,BackendDAE.SHARED(knvars,exobj,av,inieqns,remeqns,constrs,cache,env,funcs,einfo,eoc,btp,symjacs)));        
       then
         BackendDAE.DAE(systs,BackendDAE.SHARED(knvars,exobj,av,inieqns,remeqns,constrs,cache,env,funcs,einfo,eoc,btp,symjacs));
   end match;
diff --git a/Compiler/BackEnd/BackendVarTransform.mo b/Compiler/BackEnd/BackendVarTransform.mo
index dc63d4a955f..53db54f71f9 100644
--- a/Compiler/BackEnd/BackendVarTransform.mo
+++ b/Compiler/BackEnd/BackendVarTransform.mo
@@ -1154,8 +1154,9 @@ algorithm
         source = DAEUtil.addSymbolicTransformationSimplifyLst(blst,source,expl1,expl2);
         eqnslst = List.map2(eqnslst,replaceEquations2,repl,{});
         eqns = replaceEquations2(eqns,repl,{});
+        eqns = optimizeIfEquation(expl2,eqnslst,eqns,{},{},source,inAcc);
       then
-        replaceEquations2(es,repl,BackendDAE.IF_EQUATION(expl2,eqnslst,eqns,source)::inAcc);
+        replaceEquations2(es,repl,eqns);
         
     case ((a :: es),repl,_)
       equation
@@ -1165,6 +1166,49 @@ algorithm
   end matchcontinue;
 end replaceEquations2;
 
+protected function optimizeIfEquation
+  input list<DAE.Exp> conditions;
+  input list<list<BackendDAE.Equation>> theneqns;
+  input list<BackendDAE.Equation> elseenqs;
+  input list<DAE.Exp> conditions1;
+  input list<list<BackendDAE.Equation>> theneqns1;
+  input DAE.ElementSource source;
+  input list<BackendDAE.Equation> inEqns;
+  output list<BackendDAE.Equation> outEqns;
+algorithm
+  outEqn := matchcontinue(conditions,theneqns,elseenqs,conditions1,theneqns1,source,inEqns)
+    local
+      DAE.Exp e;
+      list<DAE.Exp> explst;
+      list<list<BackendDAE.Equation>> eqnslst;
+      list<BackendDAE.Equation> eqns; 
+      
+    // no true case left with condition<>false
+    case ({},{},_,{},{},_,_) 
+      then 
+        listAppend(elseenqs,inEqns);   
+    // true case left with condition<>false
+    case ({},{},_,_,_,_,_)
+      equation 
+        explst = listReverse(conditions1);  
+        eqnslst = listReverse(theneqns1);  
+      then 
+        BackendDAE.IF_EQUATION(explst,eqnslst,elseenqs,source)::inEqns;
+    // if true use it
+    case(DAE.BCONST(true)::_,eqns::_,_,_,_,_,_)
+      then 
+        eqns; 
+    // if false skip it
+    case(DAE.BCONST(false)::explst,_::eqnslst,_,_,_,_,_)
+      then
+        optimizeIfEquation(explst,eqnslst,elseenqs,conditions1,theneqns1,source,inEqns);
+    // all other cases
+    case(e::explst,eqns::eqnslst,_,_,_,_,_)
+      then
+        optimizeIfEquation(explst,eqnslst,elseenqs,e::conditions1,eqns::theneqns1,source,inEqns);
+  end matchcontinue;
+end optimizeIfEquation;
+
 protected function replaceWhenEquation "Replaces variables in a when equation"
   input BackendDAE.WhenEquation whenEqn;
   input VariableReplacements repl;
diff --git a/Compiler/Util/Flags.mo b/Compiler/Util/Flags.mo
index 9ba48bf9e4b..32efae6fbbe 100644
--- a/Compiler/Util/Flags.mo
+++ b/Compiler/Util/Flags.mo
@@ -499,7 +499,7 @@ constant ConfigFlag NO_SIMPLIFY = CONFIG_FLAG(11, "noSimplify",
 protected constant String removeSimpleEquationDesc = "Performs alias elimination and removes constant variables from the DAE, replacing all occurrences of the old variable reference with the new value (constants) or variable reference (alias elimination).";
 public constant ConfigFlag PRE_OPT_MODULES = CONFIG_FLAG(12, "preOptModules",
   NONE(), EXTERNAL(), STRING_LIST_FLAG({
-    "evaluateParameters",
+//    "evaluateParameters",
     "removeFinalParameters", 
     "removeEqualFunctionCalls",
     "partitionIndependentBlocks",